O,S{40 -Dialkyl-S-hydrocarbylthioalkyl dithiophosphates

ABSTRACT

O,S&#39;&#39;-dialkyl-S-hydrocarbylthioalkyl dithiophosphates can be prepared by the selective dealkylation-alkylation of the corresponding O,O&#39;&#39;-dialkyl dithiophosphate esters. The C1 to C2 O-alkyl C3 to C4 S&#39;&#39;-alkyl S-hydrocarbylthioalkyl dithiophosphate products show unexpectedly high effectiveness as pesticides.

United States Patent [191 Oswald et a1.

[ Dec. 16, 1975 O,S-DIALKYL-S-HYDROCARBYLTHIOAL- KYL DITHIOPHOSPHATES[75] Inventors: Alexis A. Oswald, Mountainside; Paul L. Valint, Jr.,Woodbridge, both of NJ.

[73] Assignee: Exxon Research & Engineering Company, Linden, NJ.

[22] Filed: July 9, 1973 [21] Appl. No.: 377,874

Related US. Application Data [60] Division of Ser. No. 173,267, Aug. 19,1971, abandoned, which is a continuation of Ser. No. 821,117, May 1,1969, abandoned.

[52] US. Cl. 260/948; 260/940; 260/949; 260/936; 260/978; 260/979;

[51] Int. Cl. C07F 9/165; AOlN 9/36 [58] Field of Search 260/948 [56]References Cited UNITED STATES PATENTS 2,881,201 4/1959 Schrader 260/948X 3,294,874 12/1966 Schrader 260/948 3,636,144 1/1972 Tsuchiya et al260/948 3,660.513 5/1972 Mueller et a1. 260/948 FOREIGN PATENTS ORAPPLICATIONS 16,875 9/1963 Japan 260/948 1,136,328 3/1963 Germany1,127,892 I 3/1966 Germany 221,534 6/1962 Austria 260/948 PrimaryExaminer-Anton H. Sutto Attorney, Agent, or Firm-Frederick H. RabinABSTRACT 10 Claims, No Drawings 1 O,S-DIALKYL-S-HYDROCARBYLTHIOALKYLDITHIOPHOSPHATES This is a division of application Ser. No. 173,267,

filed on Aug. 19, 1971, which isa continuation of application Ser. No.821,117 filed on May 1, 1969, both now abandoned.

FIELD OF THE INVENTION This invention relates to new O,S'-dialkyl S-hydrocarbylthioalkyl dithiophosphates, formulations or compositionsthereof, and processes or methods of preparing and using the same. Moreparticularly, this invention relates to the preparation of C, to CO-alkyl C to C S-alkyl S'-hydrocarbylthioalkyl dithiophosphates by meansof a selective two-step process comprising the dealkylation of thecorresponding C to C 0,0-dialkyl hydrocarbylthioalkyl dithiophosphatesfollowed by alkylation. The particular products have been found to besurprisingly superior pesticides to related known compounds.

PRIOR ART 0,0'-dialkyl- 'S-hydrocarbylthioalkyl dithiophosphatesrepresent a commercially important classof insecticides. Their synthesisand pesticidal action is I described by Gerhard Schrader on pages338-427 of his monograph, entitled Die Entwicklung Neuer InsektiziderPhosphorsaure-Ester, which was published by Verlag Chemie Gmbh., inWeinheim, W. Germany in 1963. Some of the isomeric O,S'-dialkylS-hydrocarbyl thioalkyl dithiophosphates are also known in the priorart. For example, the synthesis of O,S'-diethyl S-2-ethylthioethyldithiophosphate has been described by Gerhard Schrader in German Pat.Nos. 1,032,247

and 1,136,328. In these patents, O,S-diethyl thiophosphoric acidchloride and O,S-diethyl dithiophosphoric acid potassium salt were therespective phosphorus reactants for the syntheses. German Pat. No.1,136,328

also describes the synthesis of an unsymmetrically sub- 40 stituteddialkyl ester of S-2-ethylthioethyl dithiophosphoric acid, i.e. ofO-ethyl S'-methyl S-2-ethylthioethyl dithiophosphate. A comparison of.the insecticidal activity of this unsymmetrical compound with those ofthe corresponding O,S'-dimethyl and O,S'-diethyl dithiophosphates in theabove patent showed that both symmetrically substituted compounds hadsuperior activity to the unsymmetrical compound. Higher O,S- dialkylhydrocarbylthioalkyl dithiophosphate esters were not known in the priorart. It was, however, generally assumed that higher dialkyldithiophosphate esters are less eflective, economically uselesspesticides.

SUMMARY OF THE INVENTION Organic dithiophosphates in general possessproperties which. make them suitable as pesticides, particularly asinsecticides. The importance of selected members of suchdithiophosphates, particularly of the 0,0- dialkyl dithiophosphateesters, has stimulated great interest in organic dithiophosphatechemistry and en- PROCESS REACT ANTS In accordance with this inventionO,S'dialkyl S- hydrocarbylthioalkyl dithiophosphates are prepared fromdithiophosphate esters selected from the group consisting ofS-hydrocarbylthioalkyl and S-alkenyl esters of 0,0'-dialkyldithiophosphoric acids. Said preparations comprise a combination ofdealkylation and alkylation reactions both in the liquid phase. Mostgenerally, this combination of reactions can be schematicallyrepresented in the following manner:

Wherein R' and R" are alkyl groups; R is a hydrocarbylthioalkyl radicalor an alkyl group having olefinic unsaturation; R is a hydrocarbylgroup; Q is a nonsubstituted or substituted alkylene group; D is adealkylating agent, preferably a nitrogen or phosphorus base or athiolate or inorganic salt; A is an alkylation agent I preferably analkyl halide, alkyl sulfonate, dialkyl sulfate, alkyl phosphate,trialkyl phosphite or the combination of such an alkylating agent withanother alkylating agent such as a thiol.

If R is a hydrocarbylthioalkyl radical, only one alkylating agent isused according to the following scheme:

wherein all the symbols are as previously defined and the additional RX'symbol represents an alkylating agent such as an alkyl halide, alkylsulfonate, alkyl phosphate, etc.

If R' is an alkyl group having olefinic unsaturation,

a combination of two types of alkylating agents is used according to thefollowing scheme:

wherein all the symbols are as previously defined, R,SH representing analiphatic or aromatic thiol, and R being a hydrogen or alkyl group.

While the present process is operative independent of the carbon numberof the aliphatic and aromatic groups in the reactants, it isnevertheless preferred to use reactants limited in molecular weight andstructure. Particularly, stringent limitations are necessary with regardto the reactants of the present process, if the superior novelpesticidal compositions are to be prepared.

The dithiophosphate reactants of the present process have molecularweights preferably below 800, most preferably below 400. Furthermore, itis preferred that R be a C, to C primary or secondary alkyl group. Morepreferably, R is a C, to C primary alkyl group. Most preferably R" isethyl and methyl; most specifically, R is ethyl.

The R group of the phosphorus reactant can be a substituted orunsubstituted thioalkyl radical having 1 to 30 carbon atoms, i.e.,having a molecular weight, preferably below.400, most preferably below200, or R can be an alkyl group having olefinic unsaturation having 1 to8 carbon atoms, i.e., having molecular weights below 100, mostpreferably below 60.

In case the dithiophosphate ester reactant has the general formula:

ll X

the preferred meaning of R is as previously defined.

R, is preferably a C, to C alkyl radical, phenyl, or a C to Csubstituted phenyl radical, more preferably the alkyl radicals are C, toC alkyl radicals, and most preferably they are C, to C alkyl groups; Qis preferably a C, to C alkylene or a C, to C, substituted alkylenegroup, more preferably a C, to C alkylene or C, to C monosubstitutedalkylene group, most preferably a C, to C alkylene group.

Non-limiting examples of suitable 0,0'-dialkyl S- hydrocarbylthioalkyldithiophosphate reactants having the above formula include thefollowing:

Diethyl methylthiomethyl dithiophosphate, dihexadecyl ethylthiopropyldithiophosphate, diethylhexyl propylthioethyl dithiophosphate, dimethylphenylthiomethyl dithiophosphate, diethyl chlorophenylthiomethyldithiophosphate, diethyl cyanotolylthioethyl dithiophosphate, diethyltrichlorophenylthiopropyl dithiophosphate, diethylmethylthiofluoropropyl dithiophosphate, diethyl propylthiocyanobutyldithiophosphate, methyl ethyl propylthiobutyl dithiophosphate, etc.

In case the dithiophosphate ester reactant has the general formula:

the preferred meaning of R is a C, to C,,, primary or secondary alkylradical, R is preferably hydrogen or a C, to C alkyl radical, the alkylradical more preferably being in the C, to C range. Nonlimiting examplesof suitable 0,0-dialkyl S-alkenyl dithiophosphate reactants include thefollowing:

Dimethyl propenyl dithiophosphate, dioctyl butenyl dithiophosphate,dihexadecyl octenyl dithiophosphate, diethyl hexadecenyldithiophosphate, diethyl vinyl dithiophosphate, dipropyl pentenyldithiophosphate, methyl ethyl hexenyl phosphate, dicyclohexyl allyldithiophosphate, diethyl cyanocrotyl dithiophosphate, diethylmethylthiopropenyl dithiophosphate, dimethyl dimethylcarboxamidovinyldithiophosphate, etc.

The dealkylating agents for the 0,0-dialkyl dithiophosphate esters arepreferably selected from the following groups:

wherein R, is hydrogen, a C, to C alkyl or monosubstituted alkyl,preferably hydrogen and C, to C alkyl, most preferably methyl, G is anitrogen or phosphorus base; R is a C, to C hydrocarbyl, preferably C,to C alkyl; M is an alkali or alkaline earth metal, or tetraalkylammonium; X is chlorine, bromine or iodine.

Nonlimiting, suitable dealkylating reagents for the 0,0'-dialkyldithiophosphate esters are exemplified by the following compounds:

I. Ammonia, propylamine, diethylamine, trimethylamine,tetramethylethylenediamine, N-methyl pyrrolidine, hydroxyethylamine,benzyldimethylamine', triethylenediamine, trimethylphosphine,tributylphosphine, phosphine and other nitrogen and phosphorus bases.

ll. Sodium methanethiolate, potassium ethanethiolate, potassiumethylxanthate, tetramethylammonium propanethiolate, sodium hydrogensulfide, and other thiolate salts.

III. Lithium chloride, sodium iodide, calcium chloride,tetrabutylammonium iodide, tetrahexylphosphonium bromide, and similarmetal and ammonium salts.

The dealkylation reaction of 0,0'-dialkyl S- hydrocarbylthioalkyldithiophosphates by nitrogen and phosphorus bases is shown by thefollowing scheme:

A similar dealkylation by thiolates is shown below:

If the dealkylating reagent is a salt, a trialkyl amine or atrialkylphosphine, the resulting products of dealkylation are phosphatesalts of ionic character. However, in the case of not completelysubstituted amines and phosphines the product is partly hydrogen bonded:

The reactions of olefinically unsaturated 0,0'-dialkyl dithiophosphates,in general occur in the manner described in our previous application,U.S. Ser. No. 749,575, now US. Pat. No. 3,662,034, whose disclosure inthis regard is incorporated herein by reference. Such reactions are apart of the present multistep process.

The dealkylation of alkylthioalkyl 0,0-dialkyl dithiophosphates alsooccurs selectively with the removal of an O-alkyl group. It issurprising to observe that the dealkylation of 2-alkylthioethyl0,0-dialkyl dithiophosphates does not result in the removal ofalkylthioethyl groups which are believed to be stabilized in the form ofthe corresponding episulfonium ions.

The alkylation of S-alkylthioalkyl O-alkyl dithiophosphate salts andcomplexes is also a highly selective process. It occurs exclusively onthe sulfur atom to yield the corresponding S-alkylthioalkyl O,S'dialkyldithiophosphates. With metal salts, for example, the following reactionoccurs.

wherein R" is a C, to C primary or secondary alkyl I group, preferably aC to C primary alkyl group, more preferably a C to C primary alkylgroup, and most preferably n-propyl group; X is the leaving group in thealkylating process, representative examples of X being bromine,chlorine, iodine, phosphate, sulfonate,. etc.

Suitable, 'nonlimiting examples of the alkylating agents include methylbromide, ethyl chloride, isopropyl iodide, hexadecyl chloride, methyltosylate, trimethyl phosphite, trimethyl phosphate, tripropyl phosphite,etc.

The net result of the dealkylation-alkylation processes from theviewpoint of the types of chemical structures involved is theisomerization of a thionothiolphosphate to a dithiolphosphate ester. Inthe case of the hydrocarbylthioalkyl dithiophosphates, these processesprovide the final pesticidal products of this inventiori. Starting withunsaturated dithiophosphates, however, necessitates the use of anadditional process step, i.e., the addition of a thiol to theunsaturated dithiolphosphate:

, 1O unsaturated dithiolphosphates, a free radical type thiol additionresults in primary sulfide derivatives, i.e., addition occurs in ananti-Markovnikov manner:

Radical type addition to vinylic dithiolphosphates, in

general, occurs in a highly selective manner In contrast, radicaladdition to internally allylic compounds yields dithiolphosphate adductshaving sulfur substitution mainly on the unsaturated carbon closer tothe phosphorus; e.g.

CH CH PROCESS CONDITIONS The unsaturated dithiophosphate reactants ofthe present invention can be advantageously prepared by the monoadditionof 0,0-dialkyl dithiophosphoric acids to dienes and acetylenes. Thehydrocarbylthioalkyl dithiophosphate reactants can be prepared bydisplacement reactions described in the Schrader monograph quotedearlier and by selective thiol additions.

The process conditions for the dealkylation and alkylation ofunsaturated dithiophosphates are described in US. Ser. No. 749,575 nowUS Pat. No. 3,662,034. The dealkylation and alkylation ofhydrocarbylthioalkyl dithiophosphates can be carried out in a similarmanner.

For the dealkylation, preferably equimolar reactants are used. However,an excess of the base reactant may be employed with advantage. Thedealkylation can be carried out with or without solvent. The use of asolvent is, however, usually preferred. The utilization of stronglypolar, neutral organic solvents such as acetonitrile, e hanol, andacetone is particularly advantageous.

Dealkylating temperaturescan vary from about 50 to about +l 50C.,preferably from about 25 to about 120C. The pressure employed is usuallyatmospheric. In the case of volatile dealkylating agents, however,superatmopheric pressures up to 50 atmospheres can be used to keep thereactants in the liquid reaction phase.

The dealkylation reaction is carried out for a time sufficient tosubstantially convert the starting dithiophosphate ester to thecorresponding salt. Reaction times ranging from 1 to 100 hours arecommon, periods ranging from 3 to 24 hours are preferred. Undulyprolonged reaction time, too severe conditions and excess dealkylatingagent may result in undesirable double dealkylation. After thedealkylation, the excess dealkylating agent is removed since it usuallyinterferes with the formation of neutral phosphate esters in thesubsequent alkylation stage.

In the alkylation process, the use of equimolar reactants is againpreferred. Especially, in the case of amineand phosphinedithiophosphatecomplexes, additional amounts of the alkylating agent can be used toreact with the base component of the complex:

The alkylation can be carried out with or without a solvent. It isusually advantageous to use a solvent. The preferred solvents are polarorganic compounds such as nitriles, ketones, alcohols, etc. Hydrocarbonsand their chlorinated derivatives such as xylene, chlorobenzene, etc.,are also suitable. An excess of the alkyl halide reactant can be used toserve as a solvent as well.

The alkylating temperatures can vary from about to 150, preferably fromabout 25 to about 120C. The temperature of the reaction mixture can bebrought up to a point where the alkylation occurs at an advantageousrate. It is often preferable, however, to heat up one reactant to thedesired reaction temperature and then to add the other.

The pressure of the alkylations is usually atmospheric. In the case ofvolatile alkyl halide reactants, however, the use of superatmosphericpressures can be preferable in order to keep them in the liquid reactionphase. Pressures up to about 50 atmospheres can be used.

Besides a possible change of elemental composition, dealkylationfollowed by alkylation leads to a structural isomerization of thephosphate ester. The combination of the two processes, for theisomerization of S-alkenyl 0,0'-dialkyl thionothiolphosphates to thecorresponding O,S'-dithiolphosphates is described in US. Ser. No.749,575. Other olefinically unsaturated thionothiolphosphates can beisomerized in a similar manner. For the synthesis of the pesticidalhydrocarbylthioalkyl O,S'-dialkyl dithiophosphates of the presentinvention, such an isomerization is followed by thiol addition. Startingwith hydrocarbylthioalkyl 0,0'-dialkyl dithiophosphates, isomerizationcan provide the desired compositions in one step, by combining thefollowing reactions:

wherein R R". Such an isomerization reaction can be carried outcatalytically since either the metal or the tetraalkyl ammonium or thetetraalkyl phosphonium halide salt is regenerated.

The amount of the salt catalyst is from 0.5 to 20%, preferably from 1 to5%. The temperature and pressure limits are the same as in the stepwisealkylation and dealkylation processes. It is important, however, to usea solvent in which the catalyst is soluble under the reactionconditions. Such solvents include ether alcohols such as ethoxyethanol.The use of higher temperatures between about 60 and about 140C. andsuperatmospheric pressures up to 50 atmospheres is preferred to achievepractical conversion rates with a small amount of the salt reactant,i.e., catalyst.

The S-organothioalkyl O,S-dialkyl dithiophosphate products of thepresent invention can be readily oxidized to the correspondingsulfoxides and sulfones:

slow [0] It is preferred to use chemical oxidants such as peroxides,particularly aqueous hydrogen peroxide, for these oxidations. Othersuitable oxidants include nitric acid, permanganates, bromine, etc. Theoxidations occur under conditions known for similar reactions of simplesulfides. Acetic acid and acetic anhydride can be used with advantagefor hydrogen peroxide oxidation because their application leads to theformation of the specially active oxidant intermediate, i.e., peraceticacid. Sulfuric acid can be also used as a catalyst.

The first oxidation step yielding the sulfoxide compound is relativelyfast. Consequently, the sulfoxide can be readily produced under mildconditions without the concurrent formation of significant amounts ofthe sulfone. Using peroxide, the sulfoxide is preferably prepared attemperatures between about 0 and 40C. For the preparation of thesulfone, temperatures preferably between 25 and C. are used.

The oxidation of S-alkylthioalkyl O,S-dialkyl dithiophosphates can beadvantageous with respect to their pesticidal use since the sulfoxideand sulfone derivatives are ordinarily expected to be more stabletowards hydrolysis as described in the earlier quoted Schradermonograph. Schrader also describes that there is evidence that suchoxidation also occurs in plants and animals and leads to highly active,systemic insecticides.

PRODUCT COMPOSITIONS The new products of the process claimed in thepresent invention are O-alkyl S-higher alkyl hydrocarbylthioalkyldithiophosphates. The new compositons are represented by the followinggeneral formula:

wherein: (a) R is an alkyl group, preferably C, to C, primary andsecondary alkyl, more preferably C, to C primary and secondary alkyl,most preferably methyl or ethyl, especially ethyl; (b) R" is an alkylgroup having three or more carbon atoms, preferably C to C, alkyl, morepreferably C to C alkyl, most preferably propyl and butyl, especiallyn-propyl and primary isobutyl; (c) R, is a C, to C substituted ornonsubstituted hydrocarbyl group, preferably C, to C alkyl, phenyl,substituted phenyl containing such exemplary substituents as halogen,alkylthio, alkylsulfonyl, cyano, alkyl, nitro, more preferably C, to Calkyl, chlorinated phenyl, most preferably C to C alkyl, 4-chlorophenyl;((1) Q is an unsubstituted or substituted alkylene group, preferablyhaving C, to C carbon atoms and, when substituted, having such exemplarysubstituents as phenyl, chlorophenyl, halogen, alkylthio, alkylsulfonyl;more preferably being C, to C alkylene and C, to C 8 monosubsn'tutedalkylene groups and most preferably, C, to C alkylene group and (e) y isO to 2, preferably 0.

The preferred compositions of the present invention include compounds ofthe following general structures:

wherein m is l or 2, preferably 2; n is 3 or 4, preferably 3; k and jare l to 4, preferably 1-3; y is 0-2, preferably 0 and the S-alkyl groupbeing most preferably n-propyl,

50 wherein m, and n are as previously defined in (a) above; k is l to 4,preferably 1; and X is hydrogen, halogen, methylthio, methylsulfonyl orcyano, etc., preferably chlorine.

More specific compositions of the present invention include:

chums ll wherein the meaning of m, n, j and y is as previously defined,and x is l to 2, preferably 1.

Most specific compositions of the present invention include:

wherein j is l to 3 and y is 0-2, preferably 0.

wherein j is l-3; and x is 1-2, preferably 1.

Non-limiting examples of the S-hydrocarbylthioalkyl O,S'-dialkyldithiophosphate compositions include, e. g.: Methylthiomethyl. O-methylS-propyl dithiophosphate, chlorophenylthiomethyl O-hexadecyl S-butyldithiophosphate, propylthiomethyl O-ethyl S'-hexadecyl dithiophosphate,hexadecylthioethyl O-ethyl S'- butyl dithiophosphate, ethylthiohexadecylO-ethyl S- propyl dithiophosphate, methylthiooctyl O-ethyl S- propyldithiophosphate, methylthiobutyl O-butyl S'- propyl dithiophosphate,xylylthiomethyl O-ethyl S'- octyl dithiosphate, butylthiopropyl O-octylS-propyl dithiophosphate, trichlorophenylthiomethyl O-ethyl S-propyldithiophosphate, bis-methylthiopropyl O- ethyl S-propyl dithiophosphate,methylsulfonylphenylthiomethyl O-ethyl S-propyl dithiophosphate,ethylsulfonylethyl O-ethyl S'-propyl dithiophosphate, ethysulfonylpropylO-ethyl S'-butyl dithiophosphate, ethylsulfonylbutyl O-ethyl S'-propyldithiophosphate, and chlorophenylsulfonyl O-ethyl S'-propyldithiophosphate.

PESTICIDE COMPOSITIONS While the above compositions are believed to beall novel and can be prepared by the process of this invention, theyhave widely different properties with respect to pesticidal activity.For economical pesticidal uses, certain novel compositions arepreferred, although in general all possess some measure of pesticidalactivity.

The novel S-hydrocarbylthioalkyl O-alkyl S-higher alkyl dithiophosphatepesticides preferably have a molecular weight of less than 800, morepreferably less than 400. For high activity, the O-alkyl group should bepreferably methyl or ethyl, most preferably ethyl. Surprisingly, theS-alkyl group should be preferably C or C, for high activity. Mostspecifically, it should be npropyl or primary i-butyl. Thehydrocarbylthioalkyl part of them'olecule should preferably have as ahydrocarbyl group a C, to C alkyl, a phenyl or C, to C substitutedphenyl such as chlorophenyl, trichlorophenyl, methylsulfonyltolyl, etc.The thioalkyl moiety should have 1 to 4 carbon atoms in the alkylenechain connecting the two sulfur atoms. This chain can be substituted,preferably with halogen and C, to C organic radicals, preferred examplesof the latter being methyl, ethyl, phenyl, chlorophenyl,methylsulfonylphenyl, etc.

The preferred pesticidal compositions contains as an active'ingredientone or more compounds of the general formula:

wherein R is methyl or ethyl, preferably ethyl; R is C -C alkyl,preferably n-propyl; y is -2, preferably 0; R is C, to C alkyl, phenyl,or C to C substituted phenyl; and Q is C to C preferably a C to Cunsubstituted or substituted alkylene group.

While many of the preferred pesticidal dithiophosphates of the presentinvention have the well known lower O-alkoxy and S-hydrocarbylthioalkylesterifying groups, their higher S'-alkyl group is believed to be novel.Most specifically these unsymmetrical compositions exhibit the presenceof S-n-propyl or S-primary-ibutyl groups. Unexpectedly, these groupscontribute very desirable, superior pesticidal properties to thesepesticidal compositions, whereas similar known unsymmetrical O,S-dialkylesters having S-methyl or S-ethyl groups, show an insecticidal activitymarkedly inferior to that of the corresponding symmetrical esters.

Among the desirable pesticidal properties, the activity of the novelcompositions against the army worm is particularly outstanding. In viewof the very high resistance of the army worm against most of the knownpest control chemicals, this activity is very important.

It is similarly unexpected and important that the novel compositionshave low toxicities against warm blooded animals and are therefore safeto use. The appearance of the low toxicity is again specificallyassociated with the presence of the S-n-propyl or S-primary isobutylgroups in these molecules. This low toxicity coupled with highpesticidal activity, i.e., high therapeutical index, is essential foranimal health applications.

As previously noted, the esters of this invention are useful aspesticides, particularly are insecticides. When used as insecticides,they are-preferably formulated with a suitable carrier or diluent orcombinations thereof.

The term carrier or diluent as used herein means a material which can beinorganic or organic and synthetic or of natural origin, with which theactive ingredient or ingredients of this invention can be mixed tofacilitate its storage, transportation and handling, and application tothe insects to be treated. The carrier is preferably biologically andchemically inert, and, as used, can be a solid or a fluid. When solidcarriers are used, they are preferably particulate, granular, orpelleted; however, other shapes and sizes of solid carriers can beemployed as well. Such preferably solid carriers can be naturallyoccurring materials; although subsequently subjected to grinding,sieving, purification, and/or other treatments including for example,gypsum, tripolyte; diatomaceous earth, mineral silicates, such as mica,vermiculite, talc, and pyrophyllite; clays of the montomorillonite,kaolinite, or attapulgite groups; or calcite and dolomite; etc. Carriersproduced synthetically, as for example, synthetic hydrated silica oxidesand synthetic calcium silicates can also be used, and many proprietaryproducts of this type are available commercially. The carrier can alsobe an elemental substance such as sulfur or carbon, preferably anactivated carbon. If the carrier possesses intrinsic cata- For somepurposes, a resinous or waxy carrier can be used, preferably one whichis solvent-soluble or thermoplastic, including fusible. Examples of suchcarriers are natural or synthetic resins such as a coumarin resin;rosin; copal; shellac; dammar; polyvinyl chloride; styrene polymers andcopolymers; a solid grade of polychlorophenol such as is available underthe registered trademark Arochlor; a bitumen an asphaltite; a wax, forexample, beeswax or a mineral wax such as paraffin wax or Montan wax, ora chlorinated mineral wax or a microcrystalline wax such as thoseavailable under the registered trademark Mikrovan Wax. Compositionscomprising said resinous or waxy carriers are preferably in a granularaor pelleted form. I

Fluid carriers can be liquids, as for example, water, or an organicfluid, including liquefied, normally gaseous materials, and can besolvents or nonsolvents for the active material. For example, thehorticultural petroleum spray oils boiling in the range of from about275 to about 575F., or boiling in the range of from about 575 to about1000F., and having an unsulfonatable residue of at least about andpreferably of at least about or mixtures of these two types of oils areparticularly suitable liquid carriers.

The carrier can be mixed or formulated with the active material duringits manufacture or at any stage subsequently. The carrier can be mixedor formulated with the active material in any proportion depending uponthe nature of the carrier. One or more carriers, moreover, can be usedin combination.

The compositions of this invention can be concentrated, suitable forstorage and transport, and contain, for example, from about 5 to aboutby'weight of the active ingredient, preferably from about 20 to about80% by weight. These concentrates can be diluted with the same or adifferent carrier to a concentration suitable for application. Thecompositions of this invention can also be dilute compositions suitablefor application in a manner well known in the art. In general,concentrations of about 0.1 to about 10% by weight of the activematerial, based upon the total weight of the composition, aresatisfactory, although lower and higher concentrations can be applied ifnecessary.

The compositions of this invention can also be formulated as dusts.These comprise an admixture of the active ingredient and a finelypowdered solid canier such as aforedescribed. The powdered carriers canbe oil-treated to improve adhesion to the surface to which they areapplied. These dusts can be concentrates, in which case a highlysorptive carrier is preferably used. These require dilution with thesame or different finely powdered carriers, which can be of lowersorptive capacity to a concentration suitable for application.

The compositions of this invention can also be formulated as wettablepowders comprising a major proportion of the active ingredient mixedwith a dispersant, i.e., a defiocculating or suspending agent, and, ifdesired, a finely divided solid carrier and/or a wetting agent. Theactive ingredient can be in particulate form or adsorbed on the carrier,and preferably constitutes at least about 10%, more preferably at leastabout 35%, by weight, of the final pesticidal composition. Theconcentration of the dispersing agent should in general be between about0.5 and about 5% by weight of the total 13 composition, although largeror smaller amounts can be used if desired.

The dispersant or dispersing agent used in the compositions orformulations of this invention can be any substance having definitedispersant, i.e., deflocculating or suspending properties as distinctfrom wetting properties, although the substances can also possesswetting properties as well.

The dispersant or dispersing agent used can be a protective colloid suchas gelatin, glue, casein, gums, or a synthetic polymeric material suchas polyvinyl alcohol and methyl cellulose, etc. Preferably, however, thedispersants or dispersing agents used are sodium or calcium salts ofhigh molecular weight sulfonic acids, as for example, the sodium orcalcium salts of lighninsulfonic acids derived from sulfite cellulosewaste liquors. The calcium or sodium salts of condensed aromaticsulfonic acids, for example, the products known as Tamol 731, are alsosuitable.

The wetting agents used can be nonionic type surfactants, as forexample, the condensation products of fatty acids containing at least12, preferably 16 to 20, carbon atoms in the molecule or abietic acid ornapthenic acid obtained in the refining of petroleum oil fractions withalkylene oxides such as ethylene oxides or propylene oxides, or withboth ethylene oxide and propylene oxide, as for example, thecondensation products of oleic acid and ethylene oxide containing about6 to ethylene oxide units in the molecule. Other nonionic wetting agentslike polyalkylene oxide polymers, commercially known as Pluronics can beused. Partial esters of the above acids with polyhydric alcohols such asglycerol, polyglycerol, sorbitol or mannitol, etc. can also be used.

Suitable anionic wetting agents include the alkali metal salts,preferably sodium salts, of sulfuric acid or sulphonic acids containingat least 10 carbon atoms in a molecule; for example, the sodiumsecondary alkyl sulfates, dialkyl sodium sulfosuccinates available underthe registered trademark Teepol, sodium sulfonates, castor oil, sodiumdodecylbenzene sulfonate, etc.

Granulated or pelleted compositions comprising a suitable carrier havingthe active ingredients incorporated therein are also included in thisinvention. These can be prepared by impregnating a granular carrier witha solution of an active ingredient or by granulatin g a mixture of afinely divided carrier and the active ingredients. The carrier used cancontain a fertilizer or a fertilizer mixture, such as for example, asuperphosphate.

The compositions of this invention can be formulated also as solutionsof the active ingredients and an organic solvent or mixtures of solvent,such as for example, alcohols; ketones, especially acetone; ethers;hydrocarbons; etc. When the toxicant itself is a liquid, it can besprayed upon the insects or fungi without further dilution.

Petroleum hydrocarbon fractions used as solvents should preferably havea flash point of about 73F an example of this being a refined aromaticextract of kerosene. Auxiliary solvents such as alcohols, ketones, andpolyalkylene glycol ethers and esters can be used in conjunction withthese petroleum solvents.

Compositions of the present invention can also be formulated asemulsifiable concentrates which are concentrated solutions ordispersions of the active ingredients in an organic liquid, preferably awater-insoluble organic liquid containing an added emulsifying agent.These concentrates can also contain a proportion of water, for example,50% by volume, based upon the total composition to facilitate subsequentdilution with water. Suitable organic liquids include, e.g., the abovepetroleum hydrocarbon fractions previously described.

The emulsifying agents or emulsifiers are generally of the typeproducing water-in-oil type emulsions which are suitable for applicationby low volume spraying, or they can be emulsifiers of the type producingoil-inwater emulsions producing concentrates which can be diluted withrelatively large volumes of water for application by high volumespraying or relatively small volumes of water for low volume spraying.In such emulsions, the active ingredient is preferably in a nonaqueousphase.

The present invention is further illustrated in greater detail by thefollowing examples, but it is to be under- 1 stood that the presentinvention, in its broadest aspects, is not necessarily limited in termsof the reactants or specific temperatures, residence times, separationtechniques, and other process conditions, etc.; or dosage levels, exposetimes, insects used, etc. by which the compounds and/or formulationsdescribed and claimed are prepared and/or used.

SYNTHESIS OF S-HYDROCARBYLTHIOALKYL O,S'-D1ALKYL DITHIOPHOSPHATES FROMTHEIR 0,0'-DIALKYL ISOMERS Example 1 O-S-Diethyl S'-2-EthylthiopropylDithiophosphate 0,0'-Diethyl S-1-(2-ethylthiopropyl) dithiophosphate(11.6 g., 0.04 mole) and 4.5 g (0.04 mole) of 1,4-diazabicyclo[2.2.2]octane, i.e., triethylenediamine, were stirred at ambienttemperature for 24 hours. The resultant viscous liquid was dissolved in100 ml. of acetonitrile and 8.7 g. (0.08 mole) of bromoethane wereadded. The solution was heated to C. for 4 hours and cooled to ambienttemperature. A white solid precipitated. This and the acetonitrile weredissolved in 50 ml. of water. The water phase then was separated andwashed with 250 ml. of ether. The combined organic layers were washedwith 50 ml. of 5% aqueous NaHCO dried over anhydrous MgSO and thesolvent removed under vacuum under pressures down to 0.1 mm Hg. Theliquid residue weighed 8.7 g. (87% pure by gas liquid chromatography,i.e., glc.)

Analyses. Calculated for C H ,O PS C, 37.47; H, 7.28; P, 10.77. Found:C, 37.28; H, 7.20; P, 10.56.

Example 2 Dithiophos- 15 Example 3 O-Ethyl S-l-Propyl S-EthylthiomethylDithiophosphate According to the procedure of Example 1, 26.0 g. (0.1mole) of 0,0'-diethyl S-ethylthiomethyl dithiophosphate, 11.2 g. (0.1mole) of triethylenediamine and 24.6 g. (0.2 mole) of 1-bromopropanewere reacted to give 10.0 g. of a residual product whose structure wasconfirmed by nuclear magnetic resonance spectroscopy (nmr).

Analyses. Calculated for C H, O PS C, 35.03; H, 6.92; P, 11.31. Found:C, 36.09; H, 6.92; P, 11.54.

Example 4 O-Ethyl S-l-Propyl S-4 Chlorophenylthiomethyl DithiophosphateAccording to the procedure of Example 1, 68.5 g (0.2 mole) of0,0-diethyl S-4-chlorophenylthiomethyl dithiophosphate, 22.4 g (0.2mole) triethylene diamine and 49.2 g (0.4 mole) of l-bromopropane werereacted to give 52 g. of a residual product whose structure wasconfirmed by nmr.

Analyses. Calculated for C H ClO PS C, 40.41; H, 5.05; P, 8.69. Found:C, 40.23; H, 5.12; P, 8.49.

Example 5 OHexadecyl S-Dodecylthio S'-4-Octylthiobutyl Dithiophosphate0,0-Dihexadecyl S-4-octylthiobutyl dithiophosphate is reacted with amole per cent excess of trimethylamine at 70C. in a closed, effectivelystirred pressure vessel to yield substantially pure O-hexadecylS-4octylthiobutyl dithiophosphoric acid hexadecyl trimethyl ammoniumsalt. After the removal of the excess trimethylamine, the salt isreacted with doclecyl bromide to give the desired product, whosestructure can be confirmed by nmr.

SYNTHESIS OF S-Hydrocarbylthioalkyl O,S-Dialkyl DITHIOPHOSPHATES FROMS-OLEFINIC DTTHIOPHOSPHATES Example 6 Preparation of O-Ethyl S-l-PropylS-2-Methylthiopropyl Dithiophosphate A quartz tube was charged with 48.0g. (0.2 mole) of O-ethyl S-l-propyl S-propenyl dithiophosphate andevacuated to 0.1 mm Hg. The tube was then cooled in adry-ice-isopropanol bath and 18.1 g. (0.37 mole) of methanethiol wereadded. The tube was sealed and irradiated in a water bath withultraviolet (UV) radiation from three 100 Watt Hanau immersion lamps at15from a distance of 6 cm. After 24 hours, the reaction was complete, asdetermined by gas chromatography (glc), and the excess methanethiol wasremoved under vacuum (0.1 mm). The residue was dissolved in 500 ml. ofether and Washed with 50 ml. of 5% aqueous sodium bicarbonate. The ethersolution was dried over anhydrous magnesium sulfate, and the solvent wasremoved under reduced pressure. The yield of O-ethyl S-l-propylS-1-(2-methylthiopropyl) dithiophosphate was 53.7 g. pure by glc). Theboiling point of the product was 127129C. at 0.08 mm Hg.

Analyses. Calculated for C H O PS C, 37.47; H,

-7.28; P, 10.77. Found: C, 37.53; H, 7.28; P, 11.34.

Example 7 O-Ethyl S-l-Propyl S'-2-Ethylthiopropyl Dithiophosphate Thiscompound was prepared from 48.0 g (0.2 mole) of O-ethyl S-l-propylS-propenyl dithiophosphate and 21.0 g. (0.33 mole) of ethanethiol underUV radiation according to the procedure of Example 6. The yield was 58.0g. (82% pure by glc). The boiling point of product was 128l29C. at 0.17mm Hg.

Analyses. Calculated for C H O PS C, 39.76; H, 7.68; P, 10.27. Found: C,39.91; H, 8.01; P, 9.73.

Example 8 O-Ethyl S-l-Propyl S-2-n-Propylthiopropyl Dithiophosphate Thiscompound was prepared from 48.0 g. (0.2 mole) of O-ethyl S-l-propylS'propenyl dithiophosphate and 23.3 g. (0.3 mole) of i-propanethiolunder UV radiation according to the procedure of Example 6. The yieldwas 55.0 g. The product decomposed upon distillation.

Analyses. Calculated for C H O PS C, 41.77; H, 7.89; P, 9.81. Found: C,41.96; H, 7.75; P, 9.47.

Example 9 O-Ethyl S-l-Propyl S-2-i-Propylthiopropyl DithiophosphateO-Ethyl S-l-propyl S'-propenyl dithiophosphate (24.0 g., 0.1 mole) and11.4 g. (0.15 mole) l-propanethiol were reacted according to theprocedure of Example 6 to give 16.0 g. of product (50% yield).

AIIHIySeS. Calculated fOI C11H25O2PS3: C, H, 7.89; P, 9.81; Found: C,42.18; H, 7.84; P, 9.35.

Example 10 O-Ethyl S-l-Propyl S'-2-n-Hexylthiopropyl DithiophosphateO-Ethyl S-l-propyl S-propenyl dithiophosphate (24.0 g. 0.1 mole) and17.5 g. (0.15 mole) l-hexanethiol were reached according to theprocedure of Example 6 to give 34.7 g. of a residual product whosestructure was confirmed by nmr.

Analyses. Calculated for C H O PS C, 46.77; H, 9.14; P, 8.69; Found: C,49.53; H, 8.66; P, 7.40.

Example 1 1 O-Ethyl S-2-Methylpropyl S-2-MethylthiopropylDithiophosphate This compound was prepared by reacting 5.08 g. (0.02mole) of O-ethyl S-1-(2-methylpropyl) S-prope- 17 nyl dithiophosphateand excess methanethiol according to Example 6 to give 2.6 g. of aresidual product, whose structure was confirmed by nmr.

Analyses. Calculated for C H O PS C, 39.76; H, 7.68; P, 10.27; Found: C,38.22; H, 6.95; P, 10.28.

Example 12 O-Ethyl S-l-Propyl S'-Methy1thiobutyl Dithiophosphate Thiscompound was prepared by reacting 8.6 g. (0.34 mole) of O-ethylS-l-propyl S'-l-butenyl dithiophosphate and excess methanethiolaccording to the procedure of Example 6 to give 5.6 g. of a residualproduct whose structure as confirmed by nmr.-

Analyses. Calculated for C O PS C, 39.76; H, 7.68; P, 10.27. Found: C,39.72 H, 7.60; P, 9.75.

Example 13 Example 14 O-Methyl S-l-Propyl S'-2-Methylthiopr0pylDithiophosphate O-Methyl S-l-propyl S-propenyl dithiophosphate (2.26 g.0.01 mole) and excess methanethiol were reacted according to theprocedure of Example 6 to give 2.0 g. of a residual product whosestructure was confirmed by nmr.

Analyses. Calculated for C H O PS C, 35.25; H, 6.94. Found: C, 31.15; H,6.41.

Example 15 O-Ethyl S-l-Butyl S-2-Methylthiopropyl Dithiophos phateO-Ethyl S- l-butyl S-propenyl dithiophosphate (7.62 g. 0.03 mole) andexcess methanethiol were reacted according to the procedure of Example 6to give 6.2 g. of a liquid residual product whose structure wasconfirmed by nmr.

Analyses: Calculated for C H O PS C,39.76; H, 7.68; P, 10.27. Found: C,40.53; H, 7.58; P, 9.50.

Example 16 Example 17 O,S-n-Dipropyl S'-2-Methylthiopropyl phateDithiophos- 18 O-S-Dipropyl S'-propenyl dithiophosphate (10.0 g. 0.039mole) and excess methanethiol were reacted according to the procedure ofExample 6 to give 10.1 g. of 84% pure product (72% yield).

Analyses. Calculated for C H O PS C, 39.76; H, 7.68; P, 10.27. Found: C,39.99; H, 7.75; P, 10.28.

Example 18 O-Octyl S-Hexadecyl S'-2-TrichlorophenylthiohexylDithiophosphate 0,0'-Dioctyl S-hexenyl dithiophosphate is dealkylated atC, with trimethylamine to yield O-octyl S-hexenyl dithiophosphoric acidoctyltrimethyl ammonium salt. The latter compound is alkylated withhexadecyl chloride also at 80 to give O-octyl S-hexadecyl S-hexenyldithiophosphate. Subsequent addition of trichlorobenzenethiol with UVinitiation provides the desired final product, whose structure can beconfirmed by nmr.

Example 19 O-Methyl S-Octyl S-2-Hexadecylthiobutyl Dithiophosphate0,0-Dimethyl S-crotyl dithiophosphate is dealkylated with ammonia, andthe resulting O-methyl S-crotyl dithiophosphoric acid methylammoniumsalt is reacted with octyl chloride to yield O-methyl S-octyl S-crotyldithiophosphate. Bis-azobutyronitrile catalyzed addition ofhexadecanethiol to the latter yields a mixture of two isomericdithiophosphate isomers, the 2-substituted S-butyl dithiophosphateisomer predominating. The structure of these isomers can be confirmed bynmr.

Example 20 O-Ethyl S-n-Propyl S-3-n-Propylthiopropyl DithiophosphateO-Ethyl S-n-propyl S-allyldithiophosphate is reacted with a 10 molarexcess of n-propanethiol under the effect of UV at 15. The progress ofthe reaction is estimated by nmr spectroscopy. After the reaction issubstantially complete the excess thiol is stripped in vacuo. The liquidresidual product is mostly the desired dithiolphosphate ester.

GENERAL EXPERIMENTAL PROCEDURE FOR BIOLOGICAL TESTING OFS-HYDROCARBYLTHIOALKYL O,S'-DIALKYL DITHIOPHOSPHATES In Examples 21-26which follow, the new dithiophosphate compositions of the presentinvention were tested in the greenhouse and in the laboratory todetermine their biological activity. Structurally related, knowncompounds, usually leading commercial compounds, were also testedside-by-side to determine the relative pesticidal effectiveness of thenew compounds.

In the insecticidal and miticidal tests, the experimental compounds weretested as aqueous emulsions. These emulsions were prepared by dissolvingthe compound in acetone and dispersing it in distilled water with TritonX-100, an alkylaryl polyether alcohol derived by the reaction ofi-octylphenol with ethylene oxide, to give spray emulsions containingthe desired concentrations of the compound. These emulsions were thenused in standard laboratory tests described below.

Mexican Bean Beetle:

Bean leaves were dipped in the emulsion of the test chemical and allowedto dry. Individual treated leaves were placed in Petri dishes and fourMexican bean beetle larvae introduced into each of the two replicatedishes.

Southern Army Worm:

Bean leaves were dipped in a formulation of the test chemical andallowed to dry. Individual treated leaves were placed in Petri dishesand four Southern Army Worm larvae introduced into each of two replicatedishes.

Mites, Contact:

Potted bean plants infested with the two-spotted spider mite were placedon a turntable and sprayed with a formulation of the test chemical. Theplants were held for days and the degree of mite control was rated after2 days.

Mites, Systemic:

Bean plants infested with the two-spotted mites were treated by applying20 ml. of the formulated test chemical to the soil.

Aphid, Contact:

Potted nasturtium plants .infested with the bean aphids were placed on aturntable and sprayed with a formulation of the test Chemical. Theplants were held for 2 days and the degree of aphid control was rated.Aphid, Systemic:

Nasturtium plants infested with the bean aphid were treated by applying20 ml. of the formulated test chemical to the soil. The degree of aphidcontrol was rated after 2 days.

Caged houseflies are sprayed with the formulated test chemical. After 2days the degree of housefly control was rated.

Corn Root Worm:

This test was done in the soil with larvae 7-10 days old in thefollowing manner. Seventy-five ml. (90-100 grams) of an air driedsoil-sand (2:1) mixture was placed in an 8-ounce plasticized cup. Tenml. of a 55 ppm. stock equivalent to 5 ppm. in soil or 10 pounds in a6-inch deep acre, was pipetted onto the surface of the soil. The cup wascapped and 1 hour later it was shaken vigorously thirty times. The capwas removed and two very young corn plants and five larvae wereintroduced. Readings on mortality were made 5 days later. Root-knotNematode:

An air-dried 2:1 soil-sand mixture 125 ml.) in an 8- ounce plasticizedcontainer was infested with a stock of root-knot nematode prepared 7-10days previously (at the rate of 6-7 grams of chopped galls per gallon ofsoil). Ten ml. of the formulated test chemical at 231 ppm. was pouredonto the surface of the soil-sand mixture to give a rate equivalent to25 pounds per 6 inch acre. The container was then capped and shakenvigorously 1 hour later. The container was kept for 5-7 days, thenshaken again, and seeded with 4 cucumber seeds by placing the seeds onthe surface and covering with one-half inch of sand. After 34 weeks theroots were examined for galls and the degree of control determined.

Cholinesterase Inhibition:

To a solution of 0.2 unit of bovine Cholinesterase in 2.97 ml. of abuffer solution containing 1 1.15 grams of disodium hydrogen phosphatedodecahydrate and 1.81 grams of potassium dihydrogen phosphate per literof water, 0.03 ml. of a solution of the test chemical in acetone wasadded. This mixture was then incubated in a water bath at 35C. for 30min. One ml. of a solution containing 100 milligrams of5,5-dithiobis-(2- nitrobenzoic acid), 100 milligrams ofacetylthiocholine iodide, and 75 ml. of the above buffer solution insufficient water to make 200 ml. was then added and the mixture againincubated in a water bath at 35C. for 30 minutes more. The amount ofinhibition of bovine cholinesterase was then determined from theabsorbance of this solution at 420 mp.(milimicron). By using a series ofsolutions of the test chemical at various concentrations in acetone, theconcentration needed for 50% inhibition was determined.

The insecticidal effectiveness of organophosphorus compounds isgenerally attributed to Cholinesterase inhibition. Determination of thecholinesterase .inhibition is widely used to estimate the insecticidalpotential of new organophosphorus compounds.

Fungicidal Tests Bean Powdery Mildew: Eradicant Test In these tests, theexperimental compounds were tested as aqueous emulsions, prepared in thesame manner as was previously described above with respect to theinsecticidal and miticidal tests.

Bean plants with fully expanded primary leaves were inoculated withspores of the powdery mildew fungus (Erysiphe polygoni). Emulsions ofthe experimental chemicals were then sprayed on the plants placed on arevolving turntable. The plants were then kept in a greenhouse for 7 to10 days. The amounts of the mildew on their primary leaves were thenrated.

Bean Rust: Eradicant Test Pinto bean plants with fully expanded primaryleaves were inoculated with spores of the bean rust fungus (Uromycesphaseoli) and incubated for 24 hours. The tests were then carried out asdescribed above for Bean Powdery Mildew.

Bean Rust: Systemic Eradicant Test Pinto bean plants were inoculated 24hours prior to use as above and the soil in the pot was then treatedwith 20 ml. of an emulsion of the test chemical. The rest of the testand the evaluation were then carried out as above for Bean PowderyMildew. Sclerotium: Soil Fungicide Test Sterilized soil was inoculatedwith Sclerotium and placed into a 4-ounce Dixie cup, and drenched with20 ml. of an emulsion of the test chemical. The cup was then incubatedfor 2 days at F. Thereafter, the amount of mycelial growth on the soilsusrface was rated and the control by the chemical estimatedaccordingly.

Example 21 The Effect of the Introduction of S-n-Propyl Group intoCommercial 0,0-Diethyl S-l-lydrocarbylthioalkyl DithiophosphatePesticides A number of leading commercial 0,0'-diethyl S-hydrocarbylthioalkyl dithiophosphate pesticides were converted to thecorresponding O-ethyl S-n-propyl S-hydrocarbylthioalkyl dithiophosphatesusing the present process as described in Examples 2-4. The

Example 22 The Effect of S-Ethyl Versus S-n-Propyl Group on thePesticidal Activity The O,S'-dialkyl S-2-alkylthiopropyl dithiophos-TABLE I Effect of the Introduction of the S-Propyl Group lnto Commercial0,0-Diethyl S-Hydrocarbylthioalkyl Pesticides C l-I 0 z)|2 1 n c,l-i,s H0 House Corn Nematodes Fly Rootworm Rate, Southern Mexican Bean SprayLarvae Control Cholinesterase Experimental Compound Army Worm BeetleLarvae Mortal- Mortalafter l-4 Inhibiting (Example No. Conc. Mortal-Conc. Mortality,%(at ity,%( at weeks (at cone. LDSO, or Trade Name) ppmity, ppm ity, ppm) 2.5 ppm) lbs/acre Mole/Liter C l-I O P( O)SCH CH SC H50 I00 50 I00 I00 20 100 l l X l 0 nC;,I-I S (C H O) P(S )scn cn sc m 500 5O I00 0 0 3 .8 X10 (Disyston) C l-I 0 P(O)SCH SC=H, I00 I00 100 100100 I00 lOO 2.7Xl0 nC H S (C H O) P( S)SCH CH SC H 100 O 100 90 90 lOO O3. 1 X10 (Thimet) C H O P(O)SCH S-@-C| 100 I00 100 I00 100" 0 100 4.l l0n-C;,H-,S

(C H O) P(S)SCH -@-Cl 100 O 100 90 80 7.9 l0" (Trithion) "-Sprayconcentration 50 ppm.

phates were selected for a study of correlations between chemicalstructure and biological activity.

In Table II below, the effect of S-ethyl versus the S-n-propyl group isshown on the insecticidal, miticidal and nematocidal activity of thecorresponding O-ethyl S-2-ethylthiopropyl dithiophosphate esters. Thedata show that the S-n-propyl compound is an effective insecticide atppm while the S-ethyl compound shows no activity at this concentration.

Table III shows the fungicidal activity of the same two compounds. Thedate show that the S-n-propyl ness, as discussed in the Schradermonograph previ- 50 compound is again active at concentrations where theously mentioned on page 1.

S-ethyl compound shows no sign of activity.

TABLE II The Effect of the S-Ethyl versus the S-n-Propyl Group on thePesticidal Activity of O-Ethyl S-Z-Ethylthio- Propyl DithiophosphateEsters Pest Control,% Experimental Routine Insecticidal and MiticidalTests Corn Nematode Compound Conc. S. Army Mex. Bean Spider Mites BeanAphids Rootworm Control Example No. R" ppm Worm Beetle Contact SystemicContact Systemic (0.25 ppm) (25lb/acre) l C H 250 O 50 50 80 0 20 20 50O O O O 0 O 7 n-C;,H 250 I00 100 100 I00 100 I00 100 50 I00 100 100 I00100 O TABLE Ill The Effect of the SEthyl versus the S n-Propyl Group onthe Fungicidal Activity of O-EthyI S-Z-Ethylthiopropyl DithiophosphateEsters C l-I :PSCH -CHSC H H 0 CH Control of Foliar Fungi (After Days),(at 200 ppm) Control Experimental Compound Bean Mildew Bean Rust BeanRust Systemic of Sclerotium,% Example No. R" Eradicant EradicantEradicant (at I00 lb/acre) l C H O O O O Example 23 The effect of theO-alkyl groups was studled on the S-n-propyl S-methylthiopropyldithiophosphate esters.

g g gfgf g ig ggs gg fii the Hlgher S Alkyl The data are shown in TableV below. They indicate After finding that the substitution of theO-ethyl by that the prfsfence of the O-ethyl group leads the best theS-n-propyl group increases pesticidal activity the 31 3 g g A q l gsystgmlc effecglyelifsshof e -me y envatlve 1s etter ecause 0 its 1g erefiect of other hlgher 8 alkyl groups was exammed' polarity, its generalcontact activity is lower. The O-n- The results are shown in Table IV.

The results Show that a" the C3 C4 s alkyl propyl derivative shows theleast activity both as a contact and as a systemic pesticide.

pounds have superior pesticidal activity to the known C -C S-alkylcompounds. The activity of the S-n-pro- 25 pyl compound was found to bethe best, followed, in decreasing order of activity, by the S-primaryisobutyl, Effect of the Structure of the S-Alkyl Group of the Example 25the S-i-propyl and the S-n-butyl compounds. Thioether Moiety on thePesticidal Activity The effect of the structure of the S-alkyl thioetherExample 24 group was examined on the 8-2 alkylthiopropyl esters Effectof the Structure of the O-Alkyl Groups on the of O-ethyl S-n-propyldithiophosphoric acid esters Pesticidal Activity having optimizedO,S-dialky1 groups.

TABLE IV The Effect of the Structure of the Higher S-Alkyl Groups on theActivity of O-Ethyl S-Alkyl S'2-Methylthiopropyl Dithio- PhosphatePesticides C H O :P-sc1-i c|i scn R"S g Experimental Compound MortalityProduced, Example Conc. Sv Army Mex. Bean Spider Mites Bean Aphids HouseNo. R ppm Worm Beetle Contact Systemic Contact Systemic Flies 6 CH CHCI-I 250 100 I00 I00 I00 I 00 I00 I00 50 I00 100 100 I00 I00 0 I00 16(CH CH 250 I00 100 100 I00 I00 80 100 50 100 0 I00 0 50 20 0 I5 CH CH CHCH 250 100 0 I00 I00 I00 40 I00 80 0 I00 0 0 0 I I (CH CHCI-l 250 I00 80I00 I00 100 I00 I00 50 I00 0 60 100 I0 45 TABLE V The Effect of theStructure of O-Alkyl Groups on the Pesticidal Activity of O-AlkylS-n-Propyl S-2Methylthiopropyl Dithiophosphates :PSCH -CHSCH n-C H S uExperimental Compound Mortality Produced, Example Conc. S. Army Mex.Bean Spider Mites Bean Beetle House No. R' ppm Worm Beetle ContactSystemic Contact Systemic Flies I4 CH; 250 100 I00 100 100 I00 I00 I0050 0 0 I00 I00 I00 I00 I00 6 CI-I CH 250 I00 I00 I 00 I00 I00 I00 I00 50100 100 100 100 I00 O 100 I7 CHQCHQCH: 250 0 I00 I00 100 20 I00 50 O 805O 0 80 O 70 25 Thedata'included in Table-VI below show that theS-methyl, -ethyland n-propyl derivatives all have about the samepesticidal activity. Higher S-alkyl derivatives such as the S-n-hexylcompound, however, show a decreased level of activity. Overall, theactivity is less sensitive to the alkyl variation in the thioether thanin the phosphorus ester groups of the molecule.

The oxidation of the thioether group to the corresponding sulfoxide andsulfone group has also relatively little effect on the activity.

Example 26 Efiect of the Structure of the Alkylene Group on thePesticidal Activity Known, commercial S-hydrocarbylthioalkyl 0,0-dialkyl dithiophosphates have a methylene or an ethylene group for thealkylene part of the molecule. In

groups having more than 4 carbon atoms show a defi- 3O nite drop inactivity. For example, the t-butyl ethylene TABLE VI compound shows verylittle insecticidal activity at 50 ppm.

Example 27 The Effect of the S-n-Propyl Group on the Toxicity TowardsWarm Blooded Animals The pesticidally effective novel O-ethyl S-n-propylS'-alkylthioalkyl compounds were also examined for their acute, oraltoxicity on rats. Conventional toxicity experiments were designed todetermine the effect on toxicity of the S-n-propyl group which is thekey group in attributing the pesticidal activity. The data are shown inTable VIII below.

Studying the first three compounds, i.e. S-ethylthioethyl O-ethyldithiophosphate derivatives, it was found that both theO,S-isomerization and replacement of an O-ethyl with an S-n-propyl groupresult in reduced toxicity. Using the present process, the new S-propylcompound with a median lethal dose, L of 318 mg/kg is produced fromDisyston having a median lethal toxicity, L of mg/kg.

The present process similarly yields S-n-propyl derivatives of reducedtoxicity in the case of S-2-alkylthiopropyl O-ethyl dithiophosphatederivatives as shown by the compounds of Examples 6-8. TheS-2-n-propylthiopropyl compound of Example 8 has a particularly lowtoxicity.

It is most surprising and advantageous that within the present new classof compounds the highly effective pesticides have low toxicities.

Effect of the Structure of the S-Alkylthioether Group on the PesticidalActivity O-Ethyl Sn-Propyl 'S-2-Alkylthiopropyl Dithiophosphates MexicanBean l-ISR Experimental Compound S. Armyworm Beetles Spider Mites BeanAphids Corn Rootworm Nematode Example Mortality, Mortality, Mortality,Mortality, Mortality, Control,

No. R (at 250 ppm) (at ppm) (at 10 ppm) (at 50 ppm) (at 2.5 ppm) (at 25lb/acre) 6 CH;, 100 100 100 100 100 I00 7 C H 100 100 100 100 I00 8n-C;,H I00 I00 100 100 100 100 9 iC;,H 100 I00 100 50 7O I00 10 nC H,100 100 90 S0 0 10 TABLE VII Effect of the Structure of the AlkyleneGroup on the Pesticidal Activity of O-Ethyl S-n-PropylS-2-Methylthioalkyl Dithiophosphates C ino PSQSCH n-C;,H;S ll 0Experimental Compound Mortality Produced at 50 ppm. Corn RootwormNematodes Example Mexican Bean Spider Bean Mortality, Control No. 1 S.Arrnyworm Beetles Mites Aphids Houseflies at 2.5 ppm at 25 lb/acre 2OCI-I CH CI-I 100 100 100 100 100 0 90 6 CH CH(CI-I;) 100 100 100 100 100I00 I00 12 CH CI-I(CH CH5) 10 100 100 I00 40 13 CH CH[C(CH O O 30 2O 80TABLE vm a)-Described in German Patent l,032,247 b)-Synthesis describedin French Patent 1,509,248.

In conclusion, it has been found in the present invention that novel,useful O-alkyl S-higher alkyl S- hydrocarbylthioalkyl dithiophosphatecompositions can be prepared by a combination of selective dealkylationand alkylation reactions. While the novel compositions are generallyuseful as animal and plant pesticides, it has been found that certaincompositions are more attractive for economical use, lesser amounts ofthese compounds being sufficient for pest control. More specifically,O-ethyl S-n-propyl S'-hydrocarbylthioalkyl dithiophosphates represent apesticidally very highly active but relatively non-toxic, novel class ofpesticides. These pesticides are particularly attractive for the controlof insects, mites, nematodes, foliar and soil fungi. Due to their highinsecticidal effectiveness and low toxicity, they have a potentiallyhigh therapeutic index for application in animal health control.

It is to be understood that the invention is not limited to thevariousembodiments and specific examples shown above since these have beenoffered merely as illustrations. Other O,S-dialkyl Shydrocarbylthioalkyldithiophosphates can be prepared and used and other modifications can bemade thereof without departing from the spirit and purview of thisinvention.

What is claimed is:

l. A compound of the general formula:

wherein k and j are from 1 to 4, and y is O to 2.

2. A compound of the general formula:

cn cn cn s y 0 wherein k and j are from 1 to 4; and Y is 0 to 2.

3. A compound of the general formula:

wherein x is l or 2; k and j are from 1 to 4, Y is 0 to 2.

4. A compound of the general formula:

wherein j is from I to 3 and y is 0 to 2.

5. A compound of the general formula:

CH3CH,CH,S 0 cu.

whereinj is l to 3, y isO to 2.

6. A compound of the formula:

mmscmcmscm, n c.H,s

7. A compound of the formula:

8. A compound of the formula:

9. A compound of the formula:

10. A compound of the formula:

1. A COMPOUND OF THE GENERAL FORMULA:
 2. A compound of the generalformula:
 3. A compound of the general formula:
 4. A compound of thegeneral formula:
 5. A compound of the general formula:
 6. A compound ofthe formula:
 7. A compound of the formula:
 8. A compound of the formula:9. A compound of the formula:
 10. A compound of the formula: